Donut tutorial: revert faces to quads?
In case you haven't appied the modifiers,  you can just remove the modifiers. See if it works or not. If it doesn't then just apply all modifiers and add a remesh modifier.  In the remesh modifier panel try either smooth or voxel. Try to turn on wireframe on to see the geometry.  Don't go crazy with the remesh settings otherwise it will drastically increase polycount and blender will crash. Hope that helps.